Locking device for pneumatic tools



June 14, 1932. MlCHEL 1,862,859

LOCKING DEVICE FOR PNEUMATIC TOOLS Fild Feb. 5, 1951 lNVE/VTOR 42% 265%! M 64 1 W Q Patented June 14, 1932 UNITED STATES PAY-TENT. OFFICE JOHN MICHEL, or GONSHOHOCKEN, PENNS LVANIA, ASSIGNOR 'ro rife? DALLETT COMPANY, or PHILADELPHIA, PENNSYLVANIA, A CORP RATIO 0 PENNSYL- VANIA LOCKING DEVICE FOR PNEUMATIC TOOLS Application filed February 3, 1931." Serial No. 513,076.

This invention relates to a device for looking a sleeve to the barrel of a pneumatic tool such as a plug drill.

Pneumatic tools are generally provided with cylindrical barrels, adapted to receive a piston, surmounted by a cap or sleeve generally providing a handle for the manipulation of the tool and forming a housing for suitable valve mechanism. Owing to the rapid vibratory action of the tool during use there is always a tendency for the sleeve to become dis engaged from the barrel. It is accordingly the object of the present invention to provide a suitable locking device for preventing a sleeve threaded on a barrel from turning relatively thereto so as to be disengaged therefrom.

It is specifically the object of the invention to provide a locking device of this type which permits assembly of the barrel and sleeve but automatically prevents relative rotation of the two members during operation while being releasable to permit the removal of the sleeve when desired.

The invention will be apparent from the following description read in conjunction with the accompanying drawing in which is illustrated one embodiment of the invention and in which;

Fig. 1 is a fragmentary view partly in section with certain parts removed;

Fig. 2 is a section taken as indicated at 22 in Fig. 1 and Fig. 3 is a detailed elevation of the locking pawl.

The invention is adapted to pneumatic tools of various types. In the specific instance here shown it is associated with parts forming the casing of a plug drill. The barrel of this tool is illustrated at 2 and the sleeve at 4, the sleevebeing threaded upon the barrel by the engagement of right-hand threads indicated at 6. The upper end of the barrel indicated at its left in Fig. 1 is provided with a series of ratchet teeth 8. The teeth 8 are engageable by the teeth 10 formed on a pawl 12 in the form of a plunger sliding within a cap 14 threaded within a tangentially extending hole in a boss provided on the sleeve. A spring 16 urges the plunger 12 vents loosening of the cap14.

inwardly. A suitable lock washer 18 pre- As illustrated most clearly in Fig. 3, the teeth 10 of the pawl are. arranged in a series along a plane tangential to the circular series of ratchet teeth on the upper end of the barrel when the plunger is in active position, as illustrated in Fig. 2. This plane forms an angle of approximately 21 with the direction of movement of the plunger 12 under the action of the spring 16. Each of the pawl teeth has an outer face forming a large angle of the order of a right angle, and preferably about with the plane above mentioned and has an inner face forming-a relatively small angle therewith, for example, about 30. Th teeth on. the barrel are oppositely formed.

By reason of the construction just illustrated, assembly is readily effected, the sleeve 4: being first threaded upon the barrelat least partially towards its limiting position where-- upon the pawl 12 is placed in position backed up by the spring: 16. Thereupon if further assembling rotation is imparted to thesleeve,

the teeth of the pawl-and of the series 8-move past each other, the pawl yielding against the action of the spring, and the inner faces of the pawl teeth readily sliding over the teeth 8 because of the small angle of their inner faces. On the other hand, once assembly is complete reverse movement is prevented since the angle of engagement between the outer faces of teeth 10 and the teeth 8 is such as to prevent sliding. It is to be noted that in this case the pawl 12 acts as a wedge, being urged to tight position by the spring 16.

What I claim and desire to protect by Letters Patent is:

1. In a pneumatic tool, a barrel, a sleeve arranged to be threaded upon the barrel, a circular series of ratchet teeth carried by the barrel, and a spring pressed wedge-shaped pawl carried by the sleeve and adapted to engage the teeth to prevent relative rotation between the sleeve and barrel in such direction as would release them from each other, said pawl being in the form of a plunger having teeth arranged in a series along a plane tangential to said series of ratchet teeth, each of the pawl teeth having an outer face forming a large angle, of the order of a right angle, with the tangent plane and an inner face forming a relatively small angle therewith, the pawl being wedged by the spring between the sleeve and barrel.

2. In a pneumatic tool, a barrel, a sleeve arranged to be threaded upon the barrel, a circular series of ratchet teeth carried by the barrel, and a spring pressed pawl carried by the sleeve and adapted to engage the teeth to prevent relative rotation between the sleeve and barrel in such direction as would release them from each other, said pawl being in the form of a plunger having teeth arranged in .a series along a plane tangential to said series of ratchet teeth, each of the pawl teeth having an outer face forming a large angle of about with the tangent plane and an inner face forming a relatively small angle of about 30 therewith.

3. In a pneumatic tool, a barrel, a sleeve arranged to be threaded upon the barrel, a circular series of ratchet teeth carried by the barrel, and a spring pressed pawl carried by the sleeve and adapted to engage the teeth to prevent relative rotation between the sleeve and barrel in such direction as would release them from each other, said pawl being in the form of a plunger having teeth arranged in a series along a plane tangential to said series of ratchet teeth, each of the pawl teeth having an outer face forming a large angle of about 85with the tangent plane and an inner face forming a relatively small angle of about 30 therewith, said pawl being guided for movement in a path making an angle of approximately 2l with said plane.

In testimony of which invention, I have hereunto set my hand, at Philadelphia, on this 24th day of January, 1931.

I JOHN MICHEL. 

